We haven't seen much of an impact from translations being read aloud so far. For people that are translating many words and phrases, voice is often slower than using a computer or phone. We also aim to differentiate by providing far more in-depth translations, examples, conjugations, phrases, pronunciations, and other tools to help people use the language correctly, which is hard to get from the voice interface.
Google's addition of showing it's own translation results has had a negative impact on portions of our traffic. When Google treated its own sites on an equal playing field, we generally outranked them. Now that they automatically put their own answers at the top for many queries, regardless of quality, we've seen a drop in some of those queries among people looking for quick translations. Fortunately, we've been able to grow in other areas where this is less of an issue.